1. Field of the Invention
The current invention generally relates to medical infusion pumps. In particular, the current invention is especially applicable to insulin pumps.
2. Description of the Related Art
Various medical infusion pumps are commercially available. A medical infusion pump infuses a medicament into a living body according to a programmed rate(s) for background (basal) doses of the medicament, and user initiated bolus doses. Insulin pumps, for example, are widely used by diabetics. To achieve the best control of diabetes, many diabetics are turning to the use of insulin pumps. An insulin pump is a device that periodically dispenses very small amounts of insulin (or suitable insulin analogs) according to a preprogrammed profile set by the user to cover basal insulin needs. Basal insulin takes care of or “covers” glucose produced by the body on a continuous basis. When a diabetic person consumes food, the diabetic person needs to estimate the amount of insulin required to cover the carbohydrates, and perhaps other food components such as protein, and program the pump to administer a bolus amount of insulin sufficient to cover the food. Typically, many insulin pump users compute the amount of carbohydrates in the food, and, using an individual carbohydrate/insulin ratio, calculate the magnitude of the bolus. For example, if known for a particular individual that one unit of insulin covers 10 grams of carbohydrates, and the meal has 100 grams of carbohydrates, the individual would program the pump to administer a bolus of 10 units of insulin. Because the bolus amount varies per meal and the diabetic person may skip a meal, an insulin pump is not preprogrammed to administer a bolus amount of insulin.
It is quite easy for a diabetic person to fail to program a bolus at mealtime. The failure to program the bolus can be either a lapse of memory or an error, such as not pushing a key on the insulin pump's keypad hard enough. If the bolus is not administered, blood sugar levels typically will rise to unhealthy and perhaps dangerous levels. Even if the person feels the high blood sugar effects, by then some harm or risk for diabetic complications have occurred. Usually a diabetic does not sense high blood glucose until the blood glucose concentration is above 400 mg/dl, whereas the usual target range for blood glucose concentration is 70 mg/dl to 120 mg/dl. While one could take more frequent blood sugar readings with available blood testing equipment, such testing is expensive and painful.
Existing medical infusion pump art includes U.S. Pat. No. 6,650,951 B1, “Method and Insulin Pump for Providing a Forgotten Bolus Warning”, which allows a user to program intervals during which boluses are expected. That is, mealtimes are entered (or defaulted), and wait times are entered (or defaulted). If a bolus is not taken between the mealtime and the mealtime plus the wait time, a warning (audio, tactile, visual) is issued. However, this invention requires programming by the user, and therefore remains susceptible to errors by the user, e.g., lack of programming by the user or incorrect programming by the user.
A need exists for a medical infusion pump that does not require the user to program expected bolus times into the medical infusion pump, but still provides one or more alerts corresponding to time intervals during which boluses are normally taken by a user.